It is known that in the timing of two-stroke internal combustion engines suitable scavenge and exhaust ports are provided, to let the fuel into the combustion engine and, respectively, to allow exhaust gas to be discharged.
However, in these engines, the height of said ports, especially the exhaust ones, depend strictly on the cylinder capacity, that is, on the maximum flow rate of the admitted fuel and exhaust gas, so that it is not possible to reduce the dimensions below a certain limit. As a result, it is not possible to utilize the whole volume available between the piston head at the bottom dead center, and the cylinder head vault. In other words, since, for the reason stated above, the actual cylinder capacity of the engine is approximately 35-40% less than the theoretical one, if a higher power is required, then it is necessary to provide a larger combustion chamber and, accordingly, a heavier and bulkier engine.